Our overall objective is to determine the extent to which light scattering measurements can be used as a tool to probe structures in normal and abnormal corneas. This is to be accomplished by quantitating light scattering through careful experimental measurements, complemented by theoretical analyses based on the structural features determined from electron microscopy (EM), from structure models, or from both. Comparisons test the validity of the structural models, or of the EM, and permit us to relate the cornea's structure to its scattering properties. Indeed we have used this method to elucidate characteristics of the fibril arrangement in the transparent normal cornea and in turbid swollen corneas, and to show that significant reductions in the fibril tension produce a small angle light scattering pattern. More recently, we used it to interpret our angular scattering measurements in terms of scattering from fibrils. We also have developed a capability to make quantitative calculations for abnormal corneas by devising a tractable direct summation of fields calculational technique and by improving our variational methods for scattering calculations. Our specific goals are to employ this methodology to examine fibrillar structures in scar tissue, to obtain more quantitative information in swollen corneas, and to follow subtle post-surgical changes in light scattering as an indication of healing. In addition, lamellar structures in normal corneas will be investigated using electron microscopy, polarized light scattering and (scanning-slit) specular microscopy. Success in these studies will give better understanding of the structural basis for the transparency and mechanical properties of normal corneas, elucidate the factors responsible for the transparency loss in scar tissue, and provide a non-invasive test of structural repair.